lower powered 700X

[Kap'n Krunch]

is anyone one on this train of a lower power set up or does a guy just practicing and learning moves feel he needs a heavier over powered 700

if you look at passed videos the 750mx in a 700 seems it had plenty of power for the average guy why is align pushing the overpowered set up ?


I'm building an even lighter set up W/kontronik 120 = no flight pack with a 750mx and running 4400 6s x2 ... even entertaining the thought of a scorpion 4035 500kv

I think it will be close to a pound lighter then aligns 700X super combo w/5000 mah... so I'm guessing... it should have a RTF in the nitro weight category but these are approximates and will weigh my build

a lighter option would be using 4100 mahs and using kontronik 700-52

any thoughts or inputs are welcome

thanks

[Smoggie]

I'm sure it will fly fine though you may hit CG problems with a very light motor and light batteries.

End of the day though the standard heli doesnt have to be 'overpowered' if you dont want it to be. The power it uses is purely a product of the rotor RPM and blade pitch... The fact that the motor is capable of 11000 W doesnt mean you will actually use 11000W. If you run lower headspeed and go easy on the collective then you will quite easily be able to cruise around at very low power with the standard setup.

PS.. the stock 130A ESC has a built in BEC so doesn't need an Rx pack.

[Thoemse]

But why? The super combo is way cheaper than what you plan building.
It can be a beast when cranked up but it can be very smooth and docile if you set it up that way.

I fly no smack 3D. I enjoy fast sportsflying with huge loops and inverted flying and stuff like that currently. For that I fly it with 1950 RPM. At that headspeed and with 5200 lipos it is good for 7 to 8 minutes of flight time!

Personally I am a big fan of the 850MX and 130A combo. The headspeed is incredibly constant. None of my other helis comes even close.

I started flying helis last summer. I am still learning and I think the 700X super combo is perfect for me. Loads of power is helpful when you are not perfect with your collective pitch.

Believe me when I say that Align picked these components very carefully. Everything just fits together.

[MotoMilt]

I wanted less headspeed (power) so I bought a 440kv motor on sale. I also had a HW130 for another project. 697 Vtx blades max efficiency is at 2050 so gearing was perfect for 440kv.
I then took the align130 and the 490kv motor and put them in a 750 Protos.
Geared for 1900
I saved 4 ounces but added a on sale 700E canopy.
All up weight 5000-12s Gens= 5100g 11.25lbs

Those servos are heavy but didn't need to make a heavy heli heavier. So I used them on the 700x.
Could save min 15g a servo with my Futaba or BK servos. Sub 5000g 11lbs Std canopy

Light enough and geared for me and the blades.

Milt

[Ace Dude]

Originally Posted by Kap'n Krunch

a lighter option would be using 4100 mahs and using kontronik 700-52

any thoughts or inputs are welcome

thanks

I'm using a Kontronik 700-45 in a different 700 size heli with 710mm blades and it works great for my needs. I fly big air and precision aerobatics. It barely comes down warm, but again, I'm not a hard core smack pilot.

[Kap'n Krunch]

Good set up ! I like flying a good mix and I would think you can still smack it with lower power you just can't push it as hard slo mo smack so to speak mostly my idea is transferring more complex move into real life with a big heli and while I don't have much experience with 700 size it's something I want to slowly ease into and keep everything as clean and controlled as possaible a good example is watching slightly older videos of Colin Bell flying nitro


I'm just wondering how the new ratio will effect the lower power motor with higher kv

[Ace Dude]

I went low Kv to maximize flight times. I don't need screaming high head speeds. ~1700rpm with 2x6s 4400mAh I'm getting about 6.5 minutes per flight. Just hovering around I can go 9 minutes with a lower head speed.

If you search this site and the other site you'll find bunch of posts about it from Gary Wright. There is also an article about it in MA last year.

Match Kv and gearing to get the head speed you want.

[Kap'n Krunch]

It seems from my understanding not that simple but anyways I'm order the 750mx and may end up with a kontronik or scorpion down the road


I actually got and airframe no motor no blades off of eBay since I'm have some reserves of compnents I can utilize in a bare airframe

Hey would you mind post a link of two for gear ratios and motor kv

Thanks

[Ace Dude]

You need to find the available pinions and gear ratios for your heli first and then check Mr. Mel's or some other head speed calculator.

[Kap'n Krunch]

Originally Posted by Ace Dude

You need to find the available pinions and gear ratios for your heli first and then check Mr. Mel's or some other head speed calculator.

No I have it just doesn't always work out either you get a hot motor hot packs or hot esc one of the three just depends none of that seems to be factored in as why I say that's the simple version by checking HS calculator

Align has it figure out with that size motor and kv that gearing is most likely optium

[Ace Dude]

Originally Posted by Kap'n Krunch

No I have it just doesn't always work out either you get a hot motor hot packs or hot esc one of the three just depends none of that seems to be factored in as why I say that's the simple version by checking HS calculator

Align has it figure out with that size motor and kv that gearing is most likely optium

The question is who is it optimum for? They guy who wants 2300rpm and 3 minute flights or the guy who only needs 1700rpm and wants 6+ minute flights.

I use low Kv motors because I want longer flight times, but I realize that's not what everyone wants.

[Xfreak3D]

do you guys use stock setup pinion 13t on the 490kv? based on mr mel... it works out around 2200rpm. . 80% gov. is it too much?

i thought 12T would be better?? 2000rpm for a 3d flights

[Thoemse]

Originally Posted by Ace Dude

I went low Kv to maximize flight times. I don't need screaming high head speeds. ~1700rpm with 2x6s 4400mAh I'm getting about 6.5 minutes per flight. Just hovering around I can go 9 minutes with a lower head speed.

If you search this site and the other site you'll find bunch of posts about it from Gary Wright. There is also an article about it in MA last year.

Match Kv and gearing to get the head speed you want.

I am getting 8 minutes of fast sportsflying with 1950RPM doing loops funnels, invertet usung the super combo. I use 5000mah 12S.
Funny enough this is my heli with the longest flighttime and it has the 850MX.

[tacomaster]

750mx is more than enough power. Here is my buddies CHP nitro converted to electric 700DFC with an xnova 4035 470kv, gensace 4500 25c, compass 700mm blades. It still has good power.

Johns Trex 700 VAM (4 min 15 sec)

[Number]

I truly believe the 750MX is enough for 90% of pilots.

Trex 700E 530KV 750MX Motor (3 min 53 sec)

It hauls that 700 around at 2200rpm with authority. It definitely bogs a bit but it doesn't seem to mind too much. Example the tic tocs at 1:45.


With 4800mAh 12s, 800MX, and 2100rpm, I get 3:30 flight times of aggressive 3D and pull about 3000mAh out of the packs. I could get quite a bit longer flights if these packs weren't so old - they've lost a fair bit of their capacity and don't perform well.

Either way, I don't find myself needing more power. The 800MX does all I need it to do and then some. If I didn't already have the 800MX, I'd consider getting a 750MX and some 4500mAh packs for it. It'd be super light.

T REX 700L Dominator (3 min 19 sec)

[Smoggie]

Originally Posted by Xfreak3D

do you guys use stock setup pinion 13t on the 490kv? based on mr mel... it works out around 2200rpm. . 80% gov. is it too much?

i thought 12T would be better?? 2000rpm for a 3d flights

The motor mount is fixed so you cant change the pinion on it's own, you have to change pinion and main gear as a set. You have two choices of gearing 13t/110t or 12t/112t. That's a pretty limited range so you need to choose a motor with the correct Kv to work with those gearings.

As the stock ESC has active freewheel it will actually govern fine down to moderately low headspeed, 1700RPM is fine even with stock gearing and 850MX Super Combo motor. I fly about 2000RPM and get 6 to 7 minutes easily with the Super Combo

[Number]

Originally Posted by Grumpy_Old_Man

The motor mount is fixed so you cant simply chane pinion. You have two choices of gearing 13t/110t or 12t/112t

As the stock ESC has active freewheel it will actually govern fine down to moderately low headspeed, 1700RPM is fine even with stock gearing.

FWIW I have a Castle 160 and have no problems running 1700rpm and doing 3D with 112/12 gearing and 520Kv. In fact the First several flights I did on my 700 were solely at 1700rpm doing 3D. The ESC never came down anything more than barely warm to the touch.

[Xfreak3D]

thanks grumpy... wow.. thats very low for esc for stock running on 2000rpm.. how many flights you have done on 13t/110T on 2000rpm ? i have burnt one esc before with 60% throttle . but thats a YPG esc 120hv frm hobbyking


thats abit turned off by align have to stick to their gear setting.. i guess a flexible mount will come soon..

[Thoemse]

850mx and 130A comes down cold when flown at 1900rpm with stock gearing.

[Smoggie]

I'm up to about 50 flights, maybe more. The ESC is always cool when i land... I'm not a hard flyer, just sports aerobatics and a few sloppy tic-tocs.

Throttle curve is about 75%, maybe a bit higher... Nowhere near as low as 60% that's for sure. I think the Align motor true Kv may be a bit lower than 490, my packs are getting on a bit which may also play a part.